Ski for snowmobile

ABSTRACT

A ski for snowmobiles in which the underface of the ski is provided with a central longitudinal groove with ground-engaging wear rods on each side of the groove, resulting in improved steerability for any snowmobile.

United States Patent 11 1 Labellle 1 June 18, 1974 SKI FOR SNOWMOBILE 2,071,220 2/1937 Schniebs 280/11.13 s inventor: Richard L. a 40 5 oo St. 2,404,402 7/1946 Porter 280/28 2,510,794 6/1950 Beerh 280/11.13 S Sherbfooke, Qufibec, Canada 3,534,972 10/1970 Salerno... 280/1 1.13 s 3,545,560 12/1970 Fox 180/5 R X [22] Sept 1972 3,675,939 7/1972 Vik 180/5 R x [21] Appl. No.: 290,704 3,726,354 4/1973 LaPlante 180/5 R 3,734,221 5 1973 L b 11 180 5 R Related us. Application Data a e e [63] Continuation-impart of Ser. No. 150,155, June 4, FOREIGN PATENTS OR APPLICATIONS 1971 P N 3 734 221 181,564 7/1936 Switzerland 280/11.13 E 612,849 5/1935 Germany 280/1 1.13 E [52] U.S. Cl. 280/28, 180/5 R, 280/1 1.13 E,

2530/1113 3 Primary Exammerbeo Friaglla [51] Int. Cl B62m 27/02 [58] Field 01 Search 280/28, 11.13 s, 11.13 E; 1 1 ABSTRACT 180/5 R A ski for snowmobiles in which the underface of the ski is provided with a central longitudinal groove with [56] References Cited ground-engaging wear rods on each side of the groove, UNITED STATES PATENTS resulting in improved steerability for any snowmobile. 905,704 12/1908 Johnson 280/28 X 5 Claims, 8 Drawing Figures mammal: w @l-WLM SHEET 2 BF 2 SKI FOR SNOWMOBILE The present application is a continuation-in-part of application Ser; No. 150,155, filed June 4, 1971 now US. Pat. No. 3,734,221, by the same applicant, and entitled: ENDLESS TRACK VEHICLE.

The present invention relates to an improved construction of the ski or skis for a snowmobile.

Conventional snowmobiles are dangerous in emergencies, because they do not steer quickly, especially on a hard surface. This is due-at least in part-to the fact that the skis have a tendency to slip laterally when the vehicle is turning.

It is accordingly the main object of the invention to provide an improved ski which greatly improves the steerability of a snowmobile.

In the annexed drawings:

FIG. 1 is a side elevation of a snowmobile provided with skis in accordance with the invention;

FIG. 2 is a side elevation of one embodiment of a ski;

FIG. 3 is a top plan view of the ski of FIG. 2;

FIG. 4 is a front end elevation of the same;

FIG. 5 is a cross-section of the same ski taken along line 5-5 of FIG. 3;

FIG. 6 is a side elevation;

FIG. 7 is a top plan view; and

FIG. 8 is a cross-section taken along line 8-8 of FIG. 7.

In the drawings, like reference characters indicate like elements throughout.

FIG. 1 shows one type of snowmobile fitted with steering skis in accordance with the invention.

The snowmobile illustrated includes a vehicle body or chassis having a front portion 1 providing a platform 2 and fitted with a front guard wall 3 extended by a transparent windshield 4..The rear portion of the chassis A forms a hood 5 having a top wall 6, side walls 7, a front wall 8 and a back wall 9. The hood 5 is hollow and is opened at its bottom, as shown at 10. The chassis forms foot-rests 11 on both sides of hood 5. A passenger seat 12 is secured on top of the hood 5 and a grab strap 13 secured to the hood 5 extends over the seat to be grasped by the rear passenger. A compartment 14 can be lifted on its hinges 14' to expose the gas filling cap 47" of a gas tank 47. The vehicle is moved by means of an endless flexible track 29 driven by an engine, not shown, located within the hood 5 and driving a sprocket wheel 37, in turn driving the endless track 29, the latter having its bottom run trained on wheels 45, 45' carried by a sub-frame 28. The hood 5 has a side opening for servicing the engine and transmission and which is normally closed by a cover 70. The engine is started by a kickdown starting lever 80 which extends through a slot 81 made in the hood 5.

The front of the vehicle is supported by a pair of ground-engaging steerable skis 15. Each ski 15 is provided with the usual leaf spring suspension 16, which is pivoted at its center for rotation about a transverse horizontal axis at 17 to the lower end of an upwardly and rearwardly inclined control rod 18 rotatably mounted within the snowmobile chassis to steer the ski while laterally tilting the same downwardly in the direction of the turning movement. The control rod 18 for each of the skis, or for one centrally located ski, if only one such ski is provided, is controlled by a suitable steering mechanism (not shown) in turn controlled by a handle 19 carried by the front guard wall 8 and accessible to the driver seated on the front portion of seat 12 with his feet on platform 2 or on foot-rests 11.

In accordance with the invention and for more efficient steering, the ski has at its ground-engaging underface a longitudinally extending central groove 22, while its longitudinal edges are downwardly bent to form flanges 23, preferably reinforced by wear rods 24 secured to the ski and running longitudinally of and inside flanges 23 on each side of central groove 22 and serving to limit the wear along the ski edges when the ski is tilted laterally and running along one edge.

The longitudinal edges of the ski are slightly concave, as shown at 25, so that the intermediate portion of the ski is of smaller width than the end portions thereof. The back end 26 of the ski is upwardly curved as well as the front end 27, so that the vehicle can be easily backed up without the rear end digging into the snow. When the ski is turned, one or the other of the wear rods 24 engages the snow or ground, resulting in much improved steerability of the vehicle.

The ski is provided at its-front end with the conventional front grip handle 28.

FIGS. 6 to 8 show another embodiment of the ski of the invention and which is easier and less expensive to manufacture than the ski of the first embodiment.

The ski 15' is of elongated shape with straight edges 29 and is wider at its front portion than at its back portion, the maximum width being about 6" and the width at the back end portion being about 4". The ski underface is provided with a longitudinally extending central groove 30 and has upwardly curved back end 31 and front end 32 to prevent digging into the snow. The groove 30 is co-extensive with the ski. The front end portion of the ski is provided with the usual hand grip 33. A pair of wear rods 34 extend on both sides of the central groove 30 and are substantially parallel therewith, said wear rods being straight when seen in top plan view and having their ends bent to provide offset portions 35 extending through holes 36 and over the top face of the ski, so as to be secured to the ski.

The front portions of the wear rods 34 extend partly along the upwardly curved front portion of the ski. The ski is provided with the usual brackets 37 for attaching the ski to the leaf spring 16 by means of the conventional hinged or slider front brackets. Here again, this embodiment has the essential feature of a central groove at theunderface of the ski with ribs on each side of the groove, the ribs in this case being provided by the wear rods 34 for selectively engaging the ground when the ski is turned and, therefore, tilted. Thus, the ski improves the steerability of the snowmobile. The ski in accordance with the second embodiment is simple and less expensive to manufacture than the first embodiment, mainly because of the elimination of the concave sides 25 and the downward flanges 23 of the ski of the first embodiment.

What I claim is:

1. A steerable ski for a snowmobile comprising an elongated flat member having at least one upwardly inclined end portion and provided at its underface with a central longitudinally extending groove and with a downwardly protruding rib along each of its two longitudinal edges, said longitudinal edges being provided with downwardly extending flanges disposed on the outside of said downwardly protruding ribs.

2. A steerable ski for a snowmobile equipped with ski mounting means which cause, when the ski is turned relative to the snowmobile, lateral tilting of the ski downwardly on the inside of the turn, comprising an elongated sheet metal member having an upwardly inclined front end portion and having an underface defining a central longitudinally extending groove, said member having longitudinal edges which, at least in the front portion of the ski, are converging towards the rear end of the ski, and a pair of spaced wear rods secured to said member and extending longitudinally of the member and protruding from the underface thereof on each side of said longitudinal groove.

3. A steerable ski as claimed in claim 2, wherein the longitudinal edges of said member are provided with downwardly extending flanges and said wear rods are disposed inside said flanges and against the same, said wear rods converging towards the rear end of the ski in the front portion of the ski.

4. A steerable ski as claimed in claim 2, wherein the intermediate portion of the member has a smaller width than the end portions thereof and said longitudinal edges are provided with downwardly extending flanges and said wear rods are disposed inside said flanges and abut the same throughout the length of the ski, whereby they have a converging diverging relation.

5. A steerable ski for a snowmobile equipped with ski mounting means which cause, when the ski is turned relative to the snowmobile, lateral tilting of the ski on the inside of the turn, comprising an elongated sheet metal member having an upwardly inclined front end portion and having an underface defining a central longitudinally extending groove and flat marginal portions on each side of the groove, said member having straight longitudinal edges converging from thefront end portion to the rear end of the ski and a pair of spaced parallel wear rods secured to said member and extending along and protruding from the respective flat marginal portions and parallel to and equally spaced from and on each side of the longitudinal groove of said member, said rods inwardly spaced from said longitudinal edges, and means for securing a leaf spring to the ski, whereby lateral tilting of the ski, when turned, causes selective and deeper ground engagement of the wear rod on the inside of the turn than the wear rod on the outside of the turn, and further lateral tilting of the ski due to further turning movement causes ground engagement by the longitudinal edge on the inside of the turn and thus gives a smaller turning radius than would be produced by the wear rod on the inside of the turn due to the inclination between the wear rod and the longitudinal edge of the member. 

1. A steerable ski for a snowmobile comprising an elongated flat member having at least one upwardly inclined end portion and provided at its underface with a central longitudinally extending groove and with a downwardly protruding rib along each of its two longitudinal edges, said longitudinal edges being provided with downwardly extending flanges disposed on the outside of said downwardly protruding ribs.
 2. A steerable ski for a snowmobile equipped with ski mounting means which cause, when the ski is turned relative to the snowmobile, lateral tilting of the ski downwardly on the inside of the turn, comprising an elongated sheet metal member having an upwardly inclined front end portion and having an undeRface defining a central longitudinally extending groove, said member having longitudinal edges which, at least in the front portion of the ski, are converging towards the rear end of the ski, and a pair of spaced wear rods secured to said member and extending longitudinally of the member and protruding from the underface thereof on each side of said longitudinal groove.
 3. A steerable ski as claimed in claim 2, wherein the longitudinal edges of said member are provided with downwardly extending flanges and said wear rods are disposed inside said flanges and against the same, said wear rods converging towards the rear end of the ski in the front portion of the ski.
 4. A steerable ski as claimed in claim 2, wherein the intermediate portion of the member has a smaller width than the end portions thereof and said longitudinal edges are provided with downwardly extending flanges and said wear rods are disposed inside said flanges and abut the same throughout the length of the ski, whereby they have a converging diverging relation.
 5. A steerable ski for a snowmobile equipped with ski mounting means which cause, when the ski is turned relative to the snowmobile, lateral tilting of the ski on the inside of the turn, comprising an elongated sheet metal member having an upwardly inclined front end portion and having an underface defining a central longitudinally extending groove and flat marginal portions on each side of the groove, said member having straight longitudinal edges converging from the front end portion to the rear end of the ski and a pair of spaced parallel wear rods secured to said member and extending along and protruding from the respective flat marginal portions and parallel to and equally spaced from and on each side of the longitudinal groove of said member, said rods inwardly spaced from said longitudinal edges, and means for securing a leaf spring to the ski, whereby lateral tilting of the ski, when turned, causes selective and deeper ground engagement of the wear rod on the inside of the turn than the wear rod on the outside of the turn, and further lateral tilting of the ski due to further turning movement causes ground engagement by the longitudinal edge on the inside of the turn and thus gives a smaller turning radius than would be produced by the wear rod on the inside of the turn due to the inclination between the wear rod and the longitudinal edge of the member. 